Golf is an excruciating game in which small misalignments of the golfer's posture, hand position, and club position at address of the ball relative to the target can be greatly magnified into an unwanted result. All players strive for ever more consistency in alignment at address and execution of a swing which will deliver an accurate stroke. Referring to FIG. 1, the general objective of proper alignment is to position the head (eyes) of the golfer along a vertical line VV bisecting the golfer's stance, the feet along a horizontal line HH aimed toward the target, and the golfer's center of gravity over the feet so as not to lean too far forward or back in the stance. The club head during the swing should sweep on the horizontal line with the sole of the club head parallel to the ground.
However, the specific alignment optimum for an individual golfer depends on many swing factors and individual factors. For different types of shots, club lengths, weights, and/or pitches, the ball (and therefore the club head at address) may be positioned forward, at center, or slightly back of the stance. The golfer's hands (and club shaft and grip) may be positioned on the line of sight to the club head, slightly forward of it, or quite a bit forward depending on the type of swing desired to be executed. The golfer's height, build, posture, body mechanics, and personal preferences must also be factored in. Therefore, the optimum alignment for an individual golfer with each particular club is subject to wide variability, even though the general objective is the same.
Throughout the years, many types of alignment sighting devices have been proposed to help a golfer see when the head, face and/or shaft of a club is aligned in the proper position relative to the golfer's line of sight to the club head. For example, U.S. Pat. No. 3,880,430 to McCabe, U.S. Pat. No. 4,136,877 to Antonius, U.S. Pat. No. 4,343,472 to Hamilton, U.S. Pat. No. 4,722,528 to Tsao, U.S. Pat. U.S. Pat. No. 5,921,868 to DiMartino, U.S. Pat. No. 6,261,190 to Ashcraft, and U.S. Pat. No. 6,394,910 to McCarthy show align devices for aligning the head or face position of putters. However, these generally are assembled or fabricated with the alignment sighting component in a fixed position which cannot be varied despite different individual factors or preferences of golfers. As a result, they are used only with putters (rather than irons or woods too) since there is much less variation in optimal alignment for individual factors and preferences. Other types of alignment sighting devices used for other clubs include sighting rods that attach to the club shaft and may be adjusted to individual preferences, but these have the problem that they are bulky or intrusive for the user when positioned on the shaft.